A normal version of a certain chromosome contains the following structure: Genes X Y Z Centromere Genes A B C. In a cell you are studying, you find a chromosome containing the structure Genes C B A Centromere A B C. What is the mostly likely explanation for this result

The formation of one isochromosome

Explanation:

In cytogenetics, an isochromosome is a structurally abnormal chromosome that renders two chromosome arms which are identical inverses of each other. An isochromosome is caused by simultaneous duplication and deletion of genetic information during DNA replication. The resulting isochromosome will contain two identical copies of either the long or short chromosome arms that are disposed as a mirror image.